Method of splicing long-length elements of a nuclear reactor into fragments and device for its implementation

ABSTRACT

The invention relates to the field of nuclear technology, in particular, to the disposal of spent long-length elements of a nuclear reactor. The invention reduces the complexity and time required to splice long-length elements and minimizes dose loads on attendants. The method of splicing long-length elements of a nuclear reactor into fragments involves placement of long-length elements inside the container and subsequent cutting. The long element is lowered into the container to its full height and cut on the level of the upper edge of the container with the separation from it of a fragment equal to the height of the container, then the upper part of the long-length element remaining after cutting is lowered inside the container to its full height and the cutting of the long-length element into fragments is repeated until it is fully spliced.

The invention relates to the field of nuclear technology, in particular,to the disposal of spent long-length elements of a nuclear reactor, andcan be used at nuclear power plants or special plants.

When decommissioning nuclear power units, it becomes necessary to splicethe technological equipment of a nuclear reactor, including long-lengthelements in the compartments of cavities of vessel internals, coolingpond of water-water energetic reactors into fragments.

Splicing of long-length elements into fragments is carried out bymechanical methods, such as saws, disk cutters, turning tools, etc., orby thermal methods, such as gas, plasma, spark cutting, etc. Devices aredeveloped, by which these methods of fragmentation are performed.

There is a method of splicing a two-beam fuel assembly of a nuclearreactor and a splicing device for its implementation according to thepatent of the Russian Federation No. 2080665, IPC (International patentclassification) G21C 19/00, G21F 7/00. This method includes theinstallation and fixation of the fuel assembly in a foldable case placedin a housing installed in a reservoir filled with water at a depthproviding biological protection. This method involves splicing the spentassembly to ensure compact storage in the spent nuclear fuel storage.

The drawback of this method is the complexity and duration of thepreparation of equipment and work.

The closest analogue of the claimed invention is the “Method of cuttinglengthy elements of a nuclear reactor” invention according to the patentof Russian Federation No 2125308, IPC G21C 19/36. The method consists insplicing the waste long-length elements of a nuclear reactor (reactorchannels, control rods, thermocouples of ionization chambers, powerdensity sensors, etc.) by transverse cutting of these elements.Long-length elements are placed inside the container, which is used asthe central part of the spent reactor channel, and they are cuttogether.

The drawback of the closest analogue is the complexity and duration ofthe splicing of long-length elements.

The problem solved by the present invention is the enhancement.

The technical result achieved by the invention, is to reduce thecomplexity and time of work on the splicing of long-length elements, aswell as to minimize the dose loads on the attendants.

The said technical result, regarding the method, is achieved due to thefact that in the method of splicing of long-length elements of a nuclearreactor into fragments, including the placement of long-length elementsinside the container and their subsequent cutting, it has been proposedto lower the long element into the container to its full height, to cutthe long-length element on the level of the upper edge of the containerwith the separation from it of a fragment equal to the height of thecontainer, then lower the upper part of the long-length elementremaining after cutting inside the container to its full height andrepeat cutting the long-length element into fragments until it is fullyspliced.

It is also proposed to carry out the splicing of -long-length elementsuntil the container is completely filled, and then the container, afterfilling it with fragments of long-length elements, is moved to thestorage location. In addition, it is proposed to carry out the splicingof long-length elements with remote control in a process reservoir underwater, the version of the container must be perforated. It is proposedto remotely control the splicing of long-length elements in the processreservoir using video surveillance and artificial lighting.

The said technical result, concerning the device, is achieved due to thefact that the device for splicing the long-length elements of a nuclearreactor into fragments, including a lock located in the processreservoir, a container installed therein and equipment for moving andcutting long-length elements of a nuclear reactor, is proposed to beadditionally equipped with video surveillance devices located in theprocess reservoir, to execute the container lock in the form of thefixed boom with container holder, installed on the bottom of the processreservoir, to execute equipment for cutting a long-length element as aremotely controlled hydraulic cutter mounted with the possibility ofmovement on a fixed boom above the container holder, and executeequipment to move a long-length element in the form of a remotelycontrolled gripping device with clamping jaws, mounted on a movableboom.

It is also proposed to make the container holder in the form of a ring,to provide a gripping device with an actuator ensuring the rotation ofthe clamping jaws. In addition, it has been proposed to provide a videosurveillance system with a general vision camera and a video cameramounted on the gripping device, and a video camera or a rigid lensedradiation-resistant endoscope mounted on a fixed boom. It is proposed toplace the floodlight lamp, and execute the container with perforatedbottom and/or walls, in the process reservoir.

Changing the method of splicing of long-length elements, in which thesplicing is carried out in the same container before it is filled, andall operations are carried out under water, leads to the achievement ofthe specified technical result.

The claimed group of inventions is illustrated with graphic material,where in FIG. 1 a device for splicing of long-length elements of anuclear reactor into fragments is shown.

A device for splicing of long-length elements of a nuclear reactor intofragments includes a container 1 holder executed in the form of a fixedboom 3 mounted on the bottom of the process reservoir 2 filled withwater, with a holder 4 of container 1, installed in the holder 4 of acontainer 1, and equipment for moving and cutting long-length elements5. The equipment for moving long-length elements 5 consists of aremotely controlled gripping device 7 with clamping jaws 8 mounted on amovable boom 6, and the equipment for cutting long-length elements 5consists of a remotely controlled hydraulic cutter 9 mounted formovement on a fixed boom 3 above the container 1 holder 4. The holder 4of the container 1 in FIG. 1 is executed as a ring. The gripping device7 is equipped with an actuator 10, providing rotation of the clampingjaws 8. Also, the device for splicing of long-length elements 5 intofragments includes a floodlight lamp 11, a general vision video camera12 and a video camera 13 mounted on the gripping device 7. On FIG. 1 aembodiment with a rigid lensed radiation-resistant endoscope 14 mountedon a fixed boom 3 is presented.

Thus, the operation of the device and the method of splicing long-lengthelements of a nuclear reactor into fragments is carried out as follows.

The container 1 for placing long-length elements 5 is installed in theholder 4 on the fixed boom 3. Using the gripping device 7 with theclamping jaws 8, the long-length element 5 is gripped in the processreservoir 2, performing the surveillance with the help of the videocamera 13. Then, the long-length element 5 is lowered into the container1 with the help of the gripping device 7 to the full height of thecontainer 1, the long-length element 5 is picked up at the level of theupper edge of the container 1, is lifted and positioned so that thehydraulic cutter 9 is directly under the clamping jaws 8 provided thatthe positioning is carried out using a rigid lensed radiation-resistantendoscope 14 mounted on a fixed boom 3. Then the cutting of thelong-length element 5 with the separation of a fragment from it isperformed and the operation of installing the remaining upper part ofthe long-length element 5 into the container 1, picking up and cuttingof the long-length element 5 to the full splicing, are repeated again.Then using the gripping device 7 the grip of the following long-lengthelement 5 in the process reservoir 2 is performed and splicing until thecontainer 1 is filled is performed. All operations are carried out in aprocess reservoir 2 filled with water with video surveillance using avideo camera 12 for general vision and additional lighting with the helpof a floodlight lamp 11. For water drainage a perforated container 1 isused. After filling with fragments of long-length elements 5, thecontainer 1 is moved to the storage location.

The claimed group of inventions provides a reduction in labourintensity, work completion time and minimization of dose loads on theattendants when splicing long-length radioactive elements of a nuclearreactor.

1. A method of splicing of long-length elements of a nuclear reactorinto fragments, including the placement of long-length elements insidethe container and their subsequent cutting, wherein the long-lengthelement is lowered into the container to its full height, thelong-length element is cut on the level of the upper edge of thecontainer with the separation from it of a fragment equal to the heightof the container, then the upper part of the long-length elementremaining after cutting inside the container is lowered to its fullheight and the cutting of long-length element into fragments until it isfully spliced, is repeated.
 2. A method of splicing long-length elementsof a nuclear reactor into fragments according to claim 1, wherein thesplicing of long-length elements is carried out until the container iscompletely filled.
 3. A method of splicing long-length elements of anuclear reactor into fragments, according to claim 1 or 2, wherein thecontainer after its filling with fragments of long-length elements ismoved to the storage location.
 4. A method of splicing long-lengthelements of a nuclear reactor into fragments according to claim 1,wherein the splicing of long-length elements is carried out with remotecontrol in the process reservoir under water.
 5. A method of splicinglong-length elements of a nuclear reactor into fragments according toclaim 1, wherein the container is perforated.
 6. A method of splicinglong-length elements of a nuclear reactor into fragments according toclaim 1, wherein the remote control long elements splicing in theprocess reservoir is carried out using video surveillance and artificiallighting.
 7. A device for splicing the long-length elements of a nuclearreactor into fragments, including a lock located in the processreservoir, a container installed therein and equipment for moving andcutting long-length elements of a nuclear reactor, wherein to beadditionally equipped with video surveillance devices located in theprocess reservoir, to execute the container lock in the form of thefixed boom with container holder, installed on the bottom of the processreservoir, to execute equipment for cutting a long-length element as aremotely controlled hydraulic cutter mounted with the possibility ofmovement on a fixed boom above the container holder, and executeequipment to move a long-length element in the form of a remotelycontrolled gripping device with clamping jaws, mounted on a movableboom.
 8. A device for splicing long-length elements of a nuclear reactorinto fragments according to claim 7, wherein the container holder ismade in the form of a ring.
 9. A device for splicing long-lengthelements of a nuclear reactor into fragments according to claim 7,wherein the gripping device is equipped with an actuator that ensuresthe rotation of the clamping jaws.
 10. A device for splicing long-lengthelements of a nuclear reactor into fragments according to claim 7,wherein the video surveillance system includes a general vision cameraand a video camera mounted on the gripping device and fixed boom.
 11. Adevice for splicing long-length elements of a nuclear reactor intofragments according to claim 7, wherein the video surveillance systemincludes a general vision camera and a video camera mounted on thegripping device and a rigid lensed radiation-resistant endoscope mountedon a fixed boom.
 12. A device for splicing long-length elements of anuclear reactor into fragments according to claim 7, wherein thefloodlight lamp is located in the process reservoir.
 13. A device forsplicing long-length elements of a nuclear reactor into fragmentsaccording to claim 7, wherein the container is perforated.